<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div id="app">
        <div>
            <span>名：</span>
            <span>
                <input type="text" v-model='firstName'>
            </span>
        </div>
        <div>
            <span>姓：</span>
            <span><input type="text" v-model='lastName'></span>
        </div>
        <div>{{fullName}}</div>
    </div>
    <script src="js/vue.js"></script>
    <script>
        var vm = new Vue({
            el: '#app',
            data: {
                firstName: 'Jim',
                lastName: 'Green',
                // fullName: 'Jim Green'
            },
            //计算属性方式也可实现
            computed: {
                fullName: function() {
                    return this.firstName + ' ' + this.lastName;
                }
            },
            //  侦听器
            watch: {
                // firstName: function(val) {
                //     this.fullName = val + ' ' + this.lastName;

                // },
                // lastName: function(val) {
                //     this.fullName = this.firstName + ' ' + val
                // }
            }
        })
    </script>
</body>

</html>